There are available word processors, such as the MacIntosh, which allow the user to define a "ruler" in which document geometry characteristics such as a left margin, right margin and indentation point may be defined. The "rulers" in such prior art word processing systems have heretofore been associated only with contiguous groups of lines. There is no easy way to change "rulers" throughout the entire document. This is particularly a problem when composing a lengthy document in which it is necessary to switch back and forth many times between interleaved rulers.
The IBM Script document composition facility allows margins and columns to be changed throughout a document. However, in order to even permit the possibility of changes throughout a document, the Script system requires the tedious and labor intensive process of embedding commands throughout the document. The need to embed commands throughout a document in the IBM Script system, makes document composition extremely tedious and very error prone, often requiring many iterations to debug the errors in the embedded commands.
Additionally, the IBM Script system precludes the user from seeing, in a form approaching final form, the document as it is being created because of the clutter due to embedded commands. The original document typically becomes very difficult to follow due to the embedded, cryptic commands which break up the actual textual material.
In prior art word processing systems, changing a ruler does not retroactively change the lines which were entered under the ruler. In many prior art word processing systems, only by changing the ruler can a differently formatted line be entered at all. Typically, once a line is entered any reformatting requires attention to the individual line.
In prior art word processing editors, the document being produced on disparate output devices has to be individually formatted for each device, if such capability is present at all. No prior art technique exists for automatically formatting of a document in parallel on different document processing output devices without requiring, at a minimum, the use of formatting commands which usually appear embedded within the document during its composition. In prior art document composition facilities, any capability for automatically formatting a document, in parallel, for different output devices has required the insertion of instructions throughout the document during its composition--which renders composition slow, tedious, painstaking and prone to errors.